1. Field of the Invention
The present invention relates to a wet prevention apparatus for a sensor of a microwave oven, and more particularly, to a wet prevention apparatus for a sensor of a microwave oven, which prevents wet from occurring in a sensor for use in a microwave oven without a separate driving gear.
2. Discussion of the Background Art
Generally, various sensors are used in a microwave oven to obtain various cooking information. As an example of the sensor, there is an infrared ray sensor for sensing a temperature inside a cooking chamber. The infrared ray sensor is mounted in a machine chamber, where various parts such as a magnetron and a fan are mounted, and senses a temperature inside the cooking chamber through a sensor hole formed at one sidewall of the cooking chamber. Vapor which occurs in the cooking chamber is entered into the machine chamber through the sensor hole, and wet occurs in the sensor due to the entered vapor. Accordingly, it is necessary to prevent wet from occurring in the sensor.
A background art wet prevention apparatus for a sensor of a microwave oven will be described with reference to FIGS. 1 and 2.
A microwave oven body 1 includes a cooking chamber 2 and a machine chamber 4. The cooking chamber 2 and the machine chamber 4 are isolated from each other by means of an isolation wall 1a. A sensor 12 which senses a temperature of the cooking chamber 2 is mounted in the machine chamber 4.
Describing the background art wet prevention apparatus for a sensor of a microwave oven in detail, a sensor bracket 5 is fixed to a predetermined position of the body 1. A sensor case 10 is rotatably mounted in the bracket 5. The sensor 12 is mounted within the sensor case 10.
A driving portion which rotates the sensor case 10 is mounted at one side of the sensor bracket 5. A step motor 13 is generally used as the driving portion. The step motor 13 transfers rotative force to the sensor case 10 through a power transmission means such as a gear 14.
The operation of the background art wet prevention apparatus for a sensor of a microwave oven will be described with reference to FIG. 2.
Since the sensor 12 must sense a temperature of the cooking chamber 12 during cooking, the sensor case 10 having the sensor 12 therein is arranged in such a manner that a filter 11 is placed toward a sensor hole 3 formed at the isolation wall 1a.
If cooking is completed, the step motor 13 is driven to rotate the sensor case 10 a predetermined angle, so that the filter 11 is not placed toward the sensor hole 3 to prevent wet from occurring in the filter 11 due to vapor entered from the cooking chamber 2 through the sensor hole 3.
However, the background art wet prevention apparatus for a sensor of a microwave oven has several problems.
First, since the background art wet prevention apparatus for a sensor has a structure which prevents wet from occurring by rotating the sensor case 10, a driving portion, i.e., a step motor 13 for rotating the sensor case 10, and the gear 14 are required. This results in complicated structure, increases the number of parts, and complicates assembly process. As a result, the manufacturing cost is also increased.
In addition, since the step motor 13 should be controlled depending on cooking course, a separate algorithm for controlling the step motor is required.
Finally, since the step motor 13, the gear 14 and the sensor case 10 are all driven, it is likely that the driving portion is wrong.